Alternative storage

Lithium-ion (Li-ion) has been the most prominent battery chemistry deployed for stationary energy storage – but quickly evolving factors are fast-tracking the exploration of alternatives that will likely remain preferable across many use cases. Most pressing among these factors is a persisting lithium shortage, driven by the automotive industry’s rapid shift to Li-ion-guzzling electric vehicles (EVs) and an increasingly intense appetite for lithium resources in consumer goods. The related increase in materials cost has also increased scrutiny of Li-ion’s shortcomings: fire risk, long-term degradation, and environmental and recycling issues.

Both industry and government leaders now cite a market need for creative, safe, and cost-effective alternatives that are not dependent on Li-ion. US Senator, Joe Manchin, and bipartisan colleagues recently called for greater government investment in non-Li-ion energy storage technologies,¹ while administration officials predict that companies offering Li-ion alternatives will hit the benchmark of 1 GWh in orders in 2023. Prudent businesses and energy providers seeking more practical technologies for their stationary energy storage projects are already discovering an increasing group of promising options, from metal-hydrogen to sodium-ion to gravity-assisted battery systems. While Li-ion will likely continue to be the standard for EVs, any of these other three battery technologies have the demand, capabilities, and growing track record to take starring roles in near-future stationary use cases.

EVs running on Li-ion create a run on Li-ion resources, driving the stationary market to explore more fitting solutions

As government requirements for zero-emission vehicles come into effect, and as automobile companies commit to bringing a wider selection of these vehicles to market, the demand on lithium production increases and the mining industry responsible for lithium supply struggles to keep pace. Experts foresee this gap in Li-ion supply and demand lasting for years.² However, there is a silver lining to this economic pressure on Li-ion supplies: the stationary renewable storage market will closely examine available emerging alternatives and, in many cases, find them superior across key variables. Until now, the stationary market has opted for Li-ion as the most available and de fac-to technology, and not necessarily because it is particularly suited for all stationary use cases.

The market shakeout caused by this Li-ion supply disruption will likely result in more efficient and appropriate technology utilisation for energy use cases up and down the cleantech revolution, because Li-ion is an ideal fit for EVs. EVs are viable due to the high energy density Li-ion batteries provide. At the same time, Li-ion batteries feature a relatively short duration power supply and rather hefty operating expenses, two factors that are acceptable in EV use cases but more detrimental with stationary power applications. From an economic perspective, EV automakers will therefore remain able to pay the premium for Li-ion supply throughout the shortage, while organisations involved with stationary energy storage will be increasingly incentivised to pursue alternatives.

Li-ion’s shortcomings for long-term stationary storage

While Li-ion functions well enough in the moderate temperatures and environments that EV drivers generally live in, the technology has more difficulties operating under extreme temperatures and conditions. As extreme environmental conditions continue to expand their global reach, organisations must consider this limitation when planning stationary Li-ion deployments. At the same time (and relatedly), Li-ion presents real risks of fire and thermal runaway, requiring extremely careful planning, maintenance, and safety measures to guard against disastrous consequences.

A confluence of factors adds up to create another major issue: Li-ion batteries face finite lifespans because they are susceptible to long-term degradation, utilise toxic materials, and (as of yet) have no global standards for labelling their compositions or enabling recycling. By their nature, Li-ion batteries contain components that require advanced techniques to separate.³ For EV applications, Li-ion battery manufacturers are far more concerned with optimising for safety and battery life, with less immediate concern for recyclability. Without standardisation and recyclability-by-design, Li-ion recycling remains inefficient and costly. These factors increase the appeal of alternative stationary energy storage technologies that avoid toxic materials, use more easily separable components, are fully recyclable, and feature longer lifespans as well.

Metal-hydrogen battery technology offers a compelling Li-ion alternative

Metal-hydrogen batteries directly address many of the concerns that Li-ion raises for stationary storage. These batteries utilise non-toxic, low-cost materials that carry zero fire or thermal runaway safety risks. Whereas Li-ion batteries can last a decade or two but display significant annual degradation that requires augmentation, metal-hydrogen batteries have tested lifespans of 30 years or more with almost no degradation, offering significantly greater cost-effectiveness the longer they run.

In a recent use case study demonstrating the promising appeal of metal-hydrogen for stationary energy storage, a major east coast utility had a test centre and small operational system with a Li-ion battery solution that reached the end of its life and needed replacement. Instead of pursuing a new Li-ion installation, the utility chose to test a metal-hydrogen battery for energy storage. The utility is exploring metal-hydrogen’s capabilities in supporting a microgrid application, as well as traditional capacity-based applications, such as solar smoothing and peak shaving. The test will also demonstrate how installing, commissioning, operating, and maintaining metal-hydrogen batteries compares with Li-ion.

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